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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2006-2007 PA Semi, Inc
4 *
5 * SMBus host driver for PA Semi PWRficient
6 */
7
8#include <linux/module.h>
9#include <linux/pci.h>
10#include <linux/kernel.h>
11#include <linux/stddef.h>
12#include <linux/sched.h>
13#include <linux/i2c.h>
14#include <linux/delay.h>
15#include <linux/slab.h>
16#include <linux/io.h>
17
18static struct pci_driver pasemi_smb_driver;
19
20struct pasemi_smbus {
21 struct pci_dev *dev;
22 struct i2c_adapter adapter;
23 unsigned long base;
24 int size;
25};
26
27/* Register offsets */
28#define REG_MTXFIFO 0x00
29#define REG_MRXFIFO 0x04
30#define REG_SMSTA 0x14
31#define REG_CTL 0x1c
32
33/* Register defs */
34#define MTXFIFO_READ 0x00000400
35#define MTXFIFO_STOP 0x00000200
36#define MTXFIFO_START 0x00000100
37#define MTXFIFO_DATA_M 0x000000ff
38
39#define MRXFIFO_EMPTY 0x00000100
40#define MRXFIFO_DATA_M 0x000000ff
41
42#define SMSTA_XEN 0x08000000
43#define SMSTA_MTN 0x00200000
44
45#define CTL_MRR 0x00000400
46#define CTL_MTR 0x00000200
47#define CTL_CLK_M 0x000000ff
48
49#define CLK_100K_DIV 84
50#define CLK_400K_DIV 21
51
52static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
53{
54 dev_dbg(&smbus->dev->dev, "smbus write reg %lx val %08x\n",
55 smbus->base + reg, val);
56 outl(val, smbus->base + reg);
57}
58
59static inline int reg_read(struct pasemi_smbus *smbus, int reg)
60{
61 int ret;
62 ret = inl(smbus->base + reg);
63 dev_dbg(&smbus->dev->dev, "smbus read reg %lx val %08x\n",
64 smbus->base + reg, ret);
65 return ret;
66}
67
68#define TXFIFO_WR(smbus, reg) reg_write((smbus), REG_MTXFIFO, (reg))
69#define RXFIFO_RD(smbus) reg_read((smbus), REG_MRXFIFO)
70
71static void pasemi_smb_clear(struct pasemi_smbus *smbus)
72{
73 unsigned int status;
74
75 status = reg_read(smbus, REG_SMSTA);
76 reg_write(smbus, REG_SMSTA, status);
77}
78
79static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
80{
81 int timeout = 10;
82 unsigned int status;
83
84 status = reg_read(smbus, REG_SMSTA);
85
86 while (!(status & SMSTA_XEN) && timeout--) {
87 msleep(1);
88 status = reg_read(smbus, REG_SMSTA);
89 }
90
91 /* Got NACK? */
92 if (status & SMSTA_MTN)
93 return -ENXIO;
94
95 if (timeout < 0) {
96 dev_warn(&smbus->dev->dev, "Timeout, status 0x%08x\n", status);
97 reg_write(smbus, REG_SMSTA, status);
98 return -ETIME;
99 }
100
101 /* Clear XEN */
102 reg_write(smbus, REG_SMSTA, SMSTA_XEN);
103
104 return 0;
105}
106
107static int pasemi_i2c_xfer_msg(struct i2c_adapter *adapter,
108 struct i2c_msg *msg, int stop)
109{
110 struct pasemi_smbus *smbus = adapter->algo_data;
111 int read, i, err;
112 u32 rd;
113
114 read = msg->flags & I2C_M_RD ? 1 : 0;
115
116 TXFIFO_WR(smbus, MTXFIFO_START | i2c_8bit_addr_from_msg(msg));
117
118 if (read) {
119 TXFIFO_WR(smbus, msg->len | MTXFIFO_READ |
120 (stop ? MTXFIFO_STOP : 0));
121
122 err = pasemi_smb_waitready(smbus);
123 if (err)
124 goto reset_out;
125
126 for (i = 0; i < msg->len; i++) {
127 rd = RXFIFO_RD(smbus);
128 if (rd & MRXFIFO_EMPTY) {
129 err = -ENODATA;
130 goto reset_out;
131 }
132 msg->buf[i] = rd & MRXFIFO_DATA_M;
133 }
134 } else {
135 for (i = 0; i < msg->len - 1; i++)
136 TXFIFO_WR(smbus, msg->buf[i]);
137
138 TXFIFO_WR(smbus, msg->buf[msg->len-1] |
139 (stop ? MTXFIFO_STOP : 0));
140 }
141
142 return 0;
143
144 reset_out:
145 reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
146 (CLK_100K_DIV & CTL_CLK_M)));
147 return err;
148}
149
150static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
151 struct i2c_msg *msgs, int num)
152{
153 struct pasemi_smbus *smbus = adapter->algo_data;
154 int ret, i;
155
156 pasemi_smb_clear(smbus);
157
158 ret = 0;
159
160 for (i = 0; i < num && !ret; i++)
161 ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1)));
162
163 return ret ? ret : num;
164}
165
166static int pasemi_smb_xfer(struct i2c_adapter *adapter,
167 u16 addr, unsigned short flags, char read_write, u8 command,
168 int size, union i2c_smbus_data *data)
169{
170 struct pasemi_smbus *smbus = adapter->algo_data;
171 unsigned int rd;
172 int read_flag, err;
173 int len = 0, i;
174
175 /* All our ops take 8-bit shifted addresses */
176 addr <<= 1;
177 read_flag = read_write == I2C_SMBUS_READ;
178
179 pasemi_smb_clear(smbus);
180
181 switch (size) {
182 case I2C_SMBUS_QUICK:
183 TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START |
184 MTXFIFO_STOP);
185 break;
186 case I2C_SMBUS_BYTE:
187 TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START);
188 if (read_write)
189 TXFIFO_WR(smbus, 1 | MTXFIFO_STOP | MTXFIFO_READ);
190 else
191 TXFIFO_WR(smbus, MTXFIFO_STOP | command);
192 break;
193 case I2C_SMBUS_BYTE_DATA:
194 TXFIFO_WR(smbus, addr | MTXFIFO_START);
195 TXFIFO_WR(smbus, command);
196 if (read_write) {
197 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
198 TXFIFO_WR(smbus, 1 | MTXFIFO_READ | MTXFIFO_STOP);
199 } else {
200 TXFIFO_WR(smbus, MTXFIFO_STOP | data->byte);
201 }
202 break;
203 case I2C_SMBUS_WORD_DATA:
204 TXFIFO_WR(smbus, addr | MTXFIFO_START);
205 TXFIFO_WR(smbus, command);
206 if (read_write) {
207 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
208 TXFIFO_WR(smbus, 2 | MTXFIFO_READ | MTXFIFO_STOP);
209 } else {
210 TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
211 TXFIFO_WR(smbus, MTXFIFO_STOP | (data->word >> 8));
212 }
213 break;
214 case I2C_SMBUS_BLOCK_DATA:
215 TXFIFO_WR(smbus, addr | MTXFIFO_START);
216 TXFIFO_WR(smbus, command);
217 if (read_write) {
218 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
219 TXFIFO_WR(smbus, 1 | MTXFIFO_READ);
220 rd = RXFIFO_RD(smbus);
221 len = min_t(u8, (rd & MRXFIFO_DATA_M),
222 I2C_SMBUS_BLOCK_MAX);
223 TXFIFO_WR(smbus, len | MTXFIFO_READ |
224 MTXFIFO_STOP);
225 } else {
226 len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX);
227 TXFIFO_WR(smbus, len);
228 for (i = 1; i < len; i++)
229 TXFIFO_WR(smbus, data->block[i]);
230 TXFIFO_WR(smbus, data->block[len] | MTXFIFO_STOP);
231 }
232 break;
233 case I2C_SMBUS_PROC_CALL:
234 read_write = I2C_SMBUS_READ;
235 TXFIFO_WR(smbus, addr | MTXFIFO_START);
236 TXFIFO_WR(smbus, command);
237 TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
238 TXFIFO_WR(smbus, (data->word >> 8) & MTXFIFO_DATA_M);
239 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
240 TXFIFO_WR(smbus, 2 | MTXFIFO_STOP | MTXFIFO_READ);
241 break;
242 case I2C_SMBUS_BLOCK_PROC_CALL:
243 len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX - 1);
244 read_write = I2C_SMBUS_READ;
245 TXFIFO_WR(smbus, addr | MTXFIFO_START);
246 TXFIFO_WR(smbus, command);
247 TXFIFO_WR(smbus, len);
248 for (i = 1; i <= len; i++)
249 TXFIFO_WR(smbus, data->block[i]);
250 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ);
251 TXFIFO_WR(smbus, MTXFIFO_READ | 1);
252 rd = RXFIFO_RD(smbus);
253 len = min_t(u8, (rd & MRXFIFO_DATA_M),
254 I2C_SMBUS_BLOCK_MAX - len);
255 TXFIFO_WR(smbus, len | MTXFIFO_READ | MTXFIFO_STOP);
256 break;
257
258 default:
259 dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
260 return -EINVAL;
261 }
262
263 err = pasemi_smb_waitready(smbus);
264 if (err)
265 goto reset_out;
266
267 if (read_write == I2C_SMBUS_WRITE)
268 return 0;
269
270 switch (size) {
271 case I2C_SMBUS_BYTE:
272 case I2C_SMBUS_BYTE_DATA:
273 rd = RXFIFO_RD(smbus);
274 if (rd & MRXFIFO_EMPTY) {
275 err = -ENODATA;
276 goto reset_out;
277 }
278 data->byte = rd & MRXFIFO_DATA_M;
279 break;
280 case I2C_SMBUS_WORD_DATA:
281 case I2C_SMBUS_PROC_CALL:
282 rd = RXFIFO_RD(smbus);
283 if (rd & MRXFIFO_EMPTY) {
284 err = -ENODATA;
285 goto reset_out;
286 }
287 data->word = rd & MRXFIFO_DATA_M;
288 rd = RXFIFO_RD(smbus);
289 if (rd & MRXFIFO_EMPTY) {
290 err = -ENODATA;
291 goto reset_out;
292 }
293 data->word |= (rd & MRXFIFO_DATA_M) << 8;
294 break;
295 case I2C_SMBUS_BLOCK_DATA:
296 case I2C_SMBUS_BLOCK_PROC_CALL:
297 data->block[0] = len;
298 for (i = 1; i <= len; i ++) {
299 rd = RXFIFO_RD(smbus);
300 if (rd & MRXFIFO_EMPTY) {
301 err = -ENODATA;
302 goto reset_out;
303 }
304 data->block[i] = rd & MRXFIFO_DATA_M;
305 }
306 break;
307 }
308
309 return 0;
310
311 reset_out:
312 reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
313 (CLK_100K_DIV & CTL_CLK_M)));
314 return err;
315}
316
317static u32 pasemi_smb_func(struct i2c_adapter *adapter)
318{
319 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
320 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
321 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
322 I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_I2C;
323}
324
325static const struct i2c_algorithm smbus_algorithm = {
326 .master_xfer = pasemi_i2c_xfer,
327 .smbus_xfer = pasemi_smb_xfer,
328 .functionality = pasemi_smb_func,
329};
330
331static int pasemi_smb_probe(struct pci_dev *dev,
332 const struct pci_device_id *id)
333{
334 struct pasemi_smbus *smbus;
335 int error;
336
337 if (!(pci_resource_flags(dev, 0) & IORESOURCE_IO))
338 return -ENODEV;
339
340 smbus = kzalloc(sizeof(struct pasemi_smbus), GFP_KERNEL);
341 if (!smbus)
342 return -ENOMEM;
343
344 smbus->dev = dev;
345 smbus->base = pci_resource_start(dev, 0);
346 smbus->size = pci_resource_len(dev, 0);
347
348 if (!request_region(smbus->base, smbus->size,
349 pasemi_smb_driver.name)) {
350 error = -EBUSY;
351 goto out_kfree;
352 }
353
354 smbus->adapter.owner = THIS_MODULE;
355 snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
356 "PA Semi SMBus adapter at 0x%lx", smbus->base);
357 smbus->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
358 smbus->adapter.algo = &smbus_algorithm;
359 smbus->adapter.algo_data = smbus;
360
361 /* set up the sysfs linkage to our parent device */
362 smbus->adapter.dev.parent = &dev->dev;
363
364 reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
365 (CLK_100K_DIV & CTL_CLK_M)));
366
367 error = i2c_add_adapter(&smbus->adapter);
368 if (error)
369 goto out_release_region;
370
371 pci_set_drvdata(dev, smbus);
372
373 return 0;
374
375 out_release_region:
376 release_region(smbus->base, smbus->size);
377 out_kfree:
378 kfree(smbus);
379 return error;
380}
381
382static void pasemi_smb_remove(struct pci_dev *dev)
383{
384 struct pasemi_smbus *smbus = pci_get_drvdata(dev);
385
386 i2c_del_adapter(&smbus->adapter);
387 release_region(smbus->base, smbus->size);
388 kfree(smbus);
389}
390
391static const struct pci_device_id pasemi_smb_ids[] = {
392 { PCI_DEVICE(0x1959, 0xa003) },
393 { 0, }
394};
395
396MODULE_DEVICE_TABLE(pci, pasemi_smb_ids);
397
398static struct pci_driver pasemi_smb_driver = {
399 .name = "i2c-pasemi",
400 .id_table = pasemi_smb_ids,
401 .probe = pasemi_smb_probe,
402 .remove = pasemi_smb_remove,
403};
404
405module_pci_driver(pasemi_smb_driver);
406
407MODULE_LICENSE("GPL");
408MODULE_AUTHOR ("Olof Johansson <olof@lixom.net>");
409MODULE_DESCRIPTION("PA Semi PWRficient SMBus driver");